com.tangosol.net.cache

Class ReadWriteBackingMap.WriteQueue

java.lang.Object

com.tangosol.util.Base

com.tangosol.license.LicensedObject

com.tangosol.license.CoherenceDataGridEdition

com.tangosol.license.CoherenceApplicationEdition

com.tangosol.license.CoherenceCommunityEdition

com.tangosol.net.cache.ReadWriteBackingMap.WriteQueue

Enclosing class:

ReadWriteBackingMap

public class ReadWriteBackingMap.WriteQueue
extends com.tangosol.license.CoherenceCommunityEdition

A queue that only releases entries after a configurable period of time.

Author:

cp 2002.10.22

Nested Class Summary

Nested classes/interfaces inherited from class com.tangosol.license.LicensedObject

com.tangosol.license.LicensedObject.LicenseData

Nested classes/interfaces inherited from class com.tangosol.util.Base

Base.LoggingWriter, Base.StackFrame

Field Summary

Fields inherited from class com.tangosol.util.Base

LOG_ALWAYS, LOG_DEBUG, LOG_ERR, LOG_INFO, LOG_MAX, LOG_MIN, LOG_QUIET, LOG_WARN, POWER_0, POWER_G, POWER_K, POWER_M, POWER_T, UNIT_D, UNIT_H, UNIT_M, UNIT_MS, UNIT_NS, UNIT_S, UNIT_US

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	WriteQueue() Construct a WriteQueue that holds write-behind entries.

Method Summary

Modifier and Type	Method and Description
boolean	accelerateEntryRipe(Binary binKey) Move the ripe time for the queued entry up to accelerate the store operation.
protected ReadWriteBackingMap.Entry	add(ReadWriteBackingMap.Entry entryNew, long cDelay) Add an entry to the queue.
Object	checkPending(Object binKey) Check for an item known to the WriteBehind queue.
void	clearPending() Clear the map of pending entries.
boolean	containsKey(Object binKey)
void	flush() Asynchronous flush, i.e. effectively mark all currently queue'd entries as ripe.
long	getDelayMillis()
int	getDelaySeconds()
protected Map	getEntryMap() Return a map of items queued to be written.
protected Map	getPendingMap() Obtain a map of entries removed from the queue, but not yet persisted to the underlying datastore.
protected LongArray	getRipeArray() Return a LongArray indexed by ripe time (when entries become eligible to be written), and associated to a list of binary keys.
boolean	isEmpty()
boolean	isFlushed() Return true iff all contents have been persisted to the underlying store.
protected boolean	isWaitingOnPending() Check whether any threads are waiting for the store operation to complete.
ReadWriteBackingMap.Entry	remove() Wait for item in the queue to ripen (to be ready to be removed), and when there is one and it is ripe, then remove and return it.
ReadWriteBackingMap.Entry	remove(long cMillis) Wait for the next item in the queue to ripen (to be ready to be removed), and remove and return it, or return null if the specified wait time has passed.
protected ReadWriteBackingMap.Entry	remove(Object binKey) Remove a key from the queue if the key is in the queue.
protected ReadWriteBackingMap.Entry	removeImmediate() Remove the first key from the queue immediately.
ReadWriteBackingMap.Entry	removeNoWait() Check for a ripe or soft-ripe item in the queue, and if there is one, return it; otherwise, return null.
void	setDelayMillis(long cMillis) Specify the number of milliseconds that an entry added to the queue will sit in the queue before being removable ("ripe").
void	setDelaySeconds(int cSeconds) Specify the number of seconds that an entry added to the queue will sit in the queue before being removable ("ripe").
protected void	setWaitingOnPending(boolean fPending) Set the flag indicating whether any threads are waiting for the pending store operation to complete.
int	size()

Methods inherited from class com.tangosol.license.CoherenceCommunityEdition

printLicense, toString

Methods inherited from class com.tangosol.license.LicensedObject

containsEdition, ensureEdition, getClassLicenseData, getClassLicenseData, getLicenseData, getLicenseFailure, isExpired, main, printLicense, retain, retain, setLicenseData

Methods inherited from class com.tangosol.util.Base

azzert, azzert, azzert, azzertFailed, breakLines, breakLines, capitalize, checkNotEmpty, checkNotNull, checkRange, computeSafeWaitTime, decimalValue, dup, dup, ensureBigDecimal, ensureClassLoader, ensureRuntimeException, ensureRuntimeException, equals, equalsDeep, err, err, err, err, err, escape, formatDateTime, getCallerStackFrame, getCommonMonitor, getCommonMonitor, getCommonMonitor, getContextClassLoader, getContextClassLoader, getDeepMessage, getErr, getLastSafeTimeMillis, getLog, getMaxDecDigits, getMaxHexDigits, getOriginalException, getOut, getProcessRandom, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mod, mod, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, randomize, randomize, randomize, read, read, read, read, read, read, read, replace, setErr, setLog, setLogEcho, setOut, sleep, toBandwidthString, toBandwidthString, toCharEscape, toCrc, toCrc, toCrc, toCrc, toCrc, toDecString, toDelimitedString, toDelimitedString, toDelimitedString, toDelimitedString, toHex, toHex, toHexDump, toHexEscape, toHexEscape, toHexEscape, toHexEscape, toHexString, toMemorySizeString, toMemorySizeString, toQuotedCharEscape, toQuotedStringEscape, toSqlString, toString, toString, toStringEscape, toUnicodeEscape, trace, trace, trace, trace, trace, trace, trace, trace, trace, truncateString, truncateString, wait

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

WriteQueue

protected WriteQueue()

Construct a WriteQueue that holds write-behind entries.

Method Detail

getDelaySeconds

public int getDelaySeconds()

Returns:

the number of seconds that an entry added to the queue will sit in the queue before being removable ("ripe")

setDelaySeconds

public void setDelaySeconds(int cSeconds)

Specify the number of seconds that an entry added to the queue will sit in the queue before being removable ("ripe").

Parameters:

cSeconds - the number of seconds to wait before allowing an entry to be removed from the queue

getDelayMillis

public long getDelayMillis()

Returns:

the number of milliseconds that an entry added to the queue will sit in the queue before being removable ("ripe")

Since:

Coherence 3.4

setDelayMillis

public void setDelayMillis(long cMillis)

Specify the number of milliseconds that an entry added to the queue will sit in the queue before being removable ("ripe").

Parameters:

cMillis - the number of milliseconds to wait before allowing an entry to be removed from the queue

Since:

Coherence 3.4

add

protected ReadWriteBackingMap.Entry add(ReadWriteBackingMap.Entry entryNew,
                                        long cDelay)

Add an entry to the queue. By specifying a cDelay that is greater than 0, persisting of this entry will be delayed with the specified number of milliseconds. Note that the delay will always be adjusted to make sure that this entry ripes no earlier than any existing ones.

Parameters:

entryNew - the entry to insert

cDelay - the number of milliseconds until the entry is considered ripe

Returns:

an old entry for the same key, if such an entry existed at the time this method was invoked; null otherwise

remove

protected ReadWriteBackingMap.Entry remove(Object binKey)

Remove a key from the queue if the key is in the queue. This method is used, for example, if an item has actually been removed from the backing map.

Parameters:

binKey - the key object

Returns:

the corresponding entry in the queue or null if the specified key was not in the queue

removeImmediate

protected ReadWriteBackingMap.Entry removeImmediate()

Remove the first key from the queue immediately.

Returns:

the first entry in the queue or null if the queue is empty

remove

public ReadWriteBackingMap.Entry remove()

Wait for item in the queue to ripen (to be ready to be removed), and when there is one and it is ripe, then remove and return it.

Returns:

the next item in the queue (it will only return null when the backing map is no longer active)

remove

public ReadWriteBackingMap.Entry remove(long cMillis)

Wait for the next item in the queue to ripen (to be ready to be removed), and remove and return it, or return null if the specified wait time has passed.

Parameters:

cMillis - the number of ms to wait for an entry to ripen; pass -1 to wait indefinitely or 0 for no wait

Returns:

the next item in the queue, or null if the wait time has passed or if the backing map is no longer active

removeNoWait

public ReadWriteBackingMap.Entry removeNoWait()

Check for a ripe or soft-ripe item in the queue, and if there is one, return it; otherwise, return null.

Unlike the remove(java.lang.Object) method, this method will also remove soft-ripe items as calculated using the write-batch factor. A soft-ripe item is an item that has been in the write-behind queue for at least the following duration:

 D' = (1.0 - F)*D

where:

 D = write-behind delay
 F = write-batch factor

Returns:

the next item in the queue if one is ripe or soft-ripe and if the backing map is active, otherwise null

size

public int size()

Returns:

the length of the queue

isEmpty

public boolean isEmpty()

Returns:

true if and only if the queue contains no items

isFlushed

public boolean isFlushed()

Return true iff all contents have been persisted to the underlying store.

Returns:

true iff all contents have been persisted to the underlying store

flush

public void flush()

Asynchronous flush, i.e. effectively mark all currently queue'd entries as ripe.

containsKey

public boolean containsKey(Object binKey)

Parameters:

binKey - the key to look for

Returns:

true if and only if the queue contains the specified key

checkPending

public Object checkPending(Object binKey)

Check for an item known to the WriteBehind queue.

Parameters:

binKey - the key object to look for

Returns:

a value from the queue or a pending map

clearPending

public void clearPending()

Clear the map of pending entries. Notify all threads that may be waiting for pending store operations to complete.

accelerateEntryRipe

public boolean accelerateEntryRipe(Binary binKey)

Move the ripe time for the queued entry up to accelerate the store operation.

Parameters:

binKey - the binary key

Returns:

true if the entry has already been stored

getEntryMap

protected Map getEntryMap()

Return a map of items queued to be written.

Returns:

the map of items queued to be written

getRipeArray

protected LongArray getRipeArray()

Return a LongArray indexed by ripe time (when entries become eligible to be written), and associated to a list of binary keys.

Returns:

a LongArray of items in the queue

getPendingMap

protected Map getPendingMap()

Obtain a map of entries removed from the queue, but not yet persisted to the underlying datastore. The returned map is not thread safe, so all access to its content must be synchronized by the caller.

Returns:

the map of items not yet persisted to the underlying datastore

isWaitingOnPending

protected boolean isWaitingOnPending()

Check whether any threads are waiting for the store operation to complete.

Returns:

true iff there is at least one waiting thread

setWaitingOnPending

protected void setWaitingOnPending(boolean fPending)

Set the flag indicating whether any threads are waiting for the pending store operation to complete.

Parameters:

fPending - the boolean value to set